Electric incandescent lamp



Feb. '25, 1958 w. w. K'IRK 2,824,995

I ELECTRIC INCANDESCENT LAMP Filed Dec. 29. 1953 Inventor: William W KirK, by M -Wai /r His Atto ney nited States Patent- ELECTRIC INCANDESCENT LAMP William W. Kirk, Lyndhurst, Ohio, assignor to General Electric Company, a corporation of New York Application December 29, 1953, Serial No. 400,893

7 Claims. (Cl. 313-271) This invention relates to electric incandescent lamps in siderable vibrations, jars or impacts, for instance in locomotive headlights, automatic mining machinery, earth moving equipment, tractors and other like equipment.

In such cases, it is highly important that the filament or light source of the lamp be so supported that the forces developed by the vibrations or shocks be sufliciently dissipated in order to prevent distortion of the hot filament such as is apt to result in premature breakage or failure of the filament with consequent short lamp life.

One form of filament supporting arrangement which has: been found to be eminently satisfactory for this purpose is disclosed and claimed in U. S. Patent No. 2,497,567, issued February 14, 1950, to J. E. Stone and assigned to the assignee of the present invention. In this particular supporting arrangement, the filament supporting end or section of a lamp mount employing a planar type filament mounted between and in the plane of a pair of leadin wires is rendered flexible in all directions by forming each of the lead-in wires or inleads, inwardly of the lamp envelope, in two individual sections and electrically and mechanically connecting them together in longitudinally aligned and separated endto-end relation by a coil spring or shock coil fitted over and bridging the gap between the separated ends of the two inlead sections and elastically gripping tightly the said inlead sections.

While such a shock mounting arrangement for the filament is satisfactory for moderate vibration and minor shocks, it has been found that under extreme shock conditions the entire lamp mount deflects laterally of the plane thereof to such an excessive extent as to cause a permanent set to occur in the shock coil. Such a permanent set not only leaves the filament of the mount off focus, where the mount is incorporated in a reflector type lamp, but also weakens the mount to further impacts.

It is an object of my invention, therefore, to provide an electric incandescent lamp having a flexible mount structure which will effectively withstand vibration and minor shocks and will not acquire a permanent displaced position when subjected to extreme shocks.

Another object of my invention is to provide an electric incandescent lamp having a filament supported therein in definite optical relation to a reflecting surface of the lamp by a flexible supporting arrangement which not only avoids the detrimental effects on the filament of lamp vibration and minor shocks but which will also maintain the position of the filament in its said optical relation to the reflectingsurface even though the mount be subjected to extreme shocks.

-In accordance with the invention, the lamp mount is provided with deflection-limiting means in the form ofcomparatively rigid but preferably yielding stop or bumper members extending laterally from the mount transversely ice to the plane thereof, with their outer or free ends spaced a predetermined distance from but engageable with the associated sloping reflector surface of the lamp to thereby limit lateral deflection of the mount to an extent less than that which would otherwise cause it to acquire a permanent displaced position.

Further objects and advantages of my invention will appear from the following description of species thereof and from the accompanying drawing.

In the drawing, Fig. 1 is a sectional view of an electric incandescent lamp according to the invention;

Fig. 2 is a sectional view on the line 2-2 of Fig. 1; and

Fig. 3 is a perspective view of a modified form of mount construction according to. the invention.

Referring to the drawing, the invention is there shown as applied to an electric incandescent lamp of the sealed beam type disclosed in -U. S. Patent 2,148,314, D. K.

Wright, and comprising a sealed glass envelope or bulb 1 consisting of preformed pressed glass reflector and cover glass sections 2 and 3, respectively,'sealed together at their peripheries by fusion, as indicated at 4. The inner surface 5 of the reflector section 2 is formed either of paraboloidal shape as shown, or' of any other desired optical shape, and is provided with a reflecting coating 6 of aluminum, silver or other similar light-reflective material.

Mounted on'the rear outer side of the reflector section 2 at the region of the apex or center thereof is a base structure 7 of the general type shown and described injUQS.

Patent 2,272,512, Cotman, and comprising a pair of terminal contacts 8, 8 in form of metal straps or lugs which are suitably fastened, as by solderingfor instance, to the closed nippled ends 9 of respective metal ferrules or thimbles 10, 10. The contact lugs 8, 8 areprovided with screw terminals 11, 11 for connecting current supply' wires thereto. The ferrules 10, 10 are formed of 'a suitable metal which will readily wet and adhere to the glass of the reflector section 2 and they are provided with skirt portions 12 which are feathered to knife edges embedded and fused in the glass of the reflector section 2 around respective openings or passageways 13 through the wall thereof. The envelope 1 is provided with an exhaust from the metal ferrules 10 in spaced relation to the envelope wall is a lamp mount stru cture 17 accordingto the invention and comprising a pair of lead-in conductors or inleads 18, 18 secured at their outermost'ends within,

the nipples 9 of the ferrulesyas by solder 19 as shown.

From the ferrules it), the lead-in conductors 18 extend through the openings 13 in the wall of the reflector section 2 and into the envelope 1 in more or less parallel spaced relation and areconnected at their innermost ends to the opposite ends of a filament 20 preferably in the form of a coiled wire of tungsten or other suitable refractory metal. The filament 20 is supported onthe conductors 18 in a position symmetrically disposed with:

respect to the focus of the reflector section 2 and it comprises a plurality of more or less side-by-side coiled sec-;

tions 21 joined by loops or bights 22 and lying in a plane approximately coinciding with that of the parallel lead-in;

conductors 18, 18. The filament 20 is connected at its ends to 'the conductors 18, 18 and is supported at the bights 22 by anchor wires23 formed at oneend: with hOOks 24 Within which the filament bights 22 are hooked.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric lamp comprising an envelope at least a portion of which is radiation-transmissive, a filament in said envelope, inner lead-in conductors anchored to and supported from the wall of said envelope at one end only of the conductors and extending into the envelope from their wall anchorages in wholly spaced relation to the envelope wall and unengaged therewith to permit lateral deflection of the conductors within the envelope, said conductors being connected at their inner ends to said filament and including intermediate resilient portions deflectable laterally of the conductors but subject to a permanent set upon deflection beyond a predetermined amount, and stop means carried by the innermost portions of said conductors aand extending toward but terminating short of the wall of said envelope so as to be engageable therewith upon deflection of said intermediate and innermost conductor portions to a degree less than the said predetermined amount.

2. An electric lamp comprising an envelope at least a portion of which is radiation-transmissive, a filament in said envelope, inner lead-in conductors anchored to and supported from the wall of said envelope at one end only of the conductors and extending into the envelope from their wall anchorages in wholly spaced relation to the envelope wall and unengaged therewith to permit lateral deflection of the conductors within the envelope, said conductors being connected at their inner ends to said filament and including intermediate resilient portions deflectable laterally of the conductors but subject to a permanent set upon deflection beyond a predetermined amount, and bumper arms secured to and extending laterally from the innermost portions of said conductors to- Ward but terminating short of the wall of said envelope so as to be engageable therewith upon deflection of said intermediate and innermost conductor portions to a degree less than the said predetermined amount.

3. An electric lamp comprising an envelope at least a portion of which is radiation-transmissive, a filament in said envelope, a pair of inner lead-in conductors anchored to and supported from the wall of said envelope at one end only of the conductors and extending into the envelope from their wall anchorages in approximately parallel relation and in wholly spaced relation to the envelope wall and unengaged therewith to permit lateral deflection of the conductors within the envelope, said conductors being connected at their inner ends to said filament and including intermediate resilient portions deflectable laterally of the conductors but subject to a permanent set upon defiecton beyond a predetermined amount, and bumper arms secured to and extending from the innermost portions of said conductors laterally of the plane thereof toward but terminating short of the wall of said envelope so as to be engageable therewith upon deflection of said intermediate and innermost conductor portions laterally of the plane thereof to a degree less than the said predetermined amount.

4. An electric lamp comprising an envelope at least a portion of which is radiation-transmissive, a filament in said envelope, lead-in conductors anchored to and supported from the wall of said envelope at one end only of the conductors and extending into the envelope from their wall anchorages in wholly spaced relation to the envelope wall and unengaged therewith to permit lateral deflection of the conductors within the envelope, said conductors each comprising separate inner and outer sections spaced apart end-to-end and the filament being supported from and electrically connected to said inner sections, bridge means insulatively and rigidly tying the said inner conductor sections together, said inner conductor sections and bridge means together providing a rigid support frame for said filament, a coil spring fitting over and gripping tightly the individual sections of each of said conductors and bridging the gap therebetween to yieldingly and electrically connect the said conductor sections together whereby to resiliently support the said filament support frame from the anchored outer conductor sections, and stop means carried by said filament support frame and extending toward but terminating short of the wall of said envelope so as to be engageable therewith upon deflection of said filament support frame to a predetermined amount less than that which would produce a permanent set in said coil springs.

5. An electric lamp of the character set forth in claim 4 wherein the said stop means comprises rigid arm members secured to the said bridge means and extending therefrom in approximately opposite directions laterally of the said filament support frame.

6. An electric lamp of the character set forth in claim 4 wherein the said stop means comprises a pair of rigid arm members secured to each of the said inner conductor sections and extending therefrom in approximately opposite directions laterally of the said filament support frame.

7. An electric lamp comprising an envelope having a concave reflecting wall portion and a radiation-transmitting portion, lead-in conductors anchored to and supported from the said concave wall portion of the envelope at one end only of the conductors and extending into the envelope from their wall anchorages in the same general direction and in wholly spaced relation to the envelope wall and unengaged therewith to permit lateral deflection of the conductors within the enevlope, said conductors each comprising separate inner and outer sections spaced apart end-to-end and the filament being supported from and electrically connected to said inner sections, bridge means insulatively and rigidly tying the said inner conductor sections together, said inner conductor sections and bridge means together providing a rigid support frame for said filament, a coil spring fitting over and gripping tightly the individual sections of each of said conductors and bridging the gap therebetween to yieldingly and electrically connect the said conductor sections together whereby to resiliently support the said filament support frame from the anchored outer conductor sections, and rigid but laterally yieldable stop arm members secured to said filament support frame and extending therefrom in approximately opposite directions laterally of the said filament support frame toward but terminating short of the said reflecting wall portion of said envelope so as to yieldingly engage therewith upon deflection of said filament support frame to a predetermined amount less than that which would produce a permanent set in said coil springs.

References Cited in the file of this patent UNITED STATES PATENTS 

